November 2006 issue
Cover illustration: This macrocycle has a `wheelchair' conformation. The `backrest' pyridine ring is tilted by 142.87 (7)° with respect to the `seat' plane, and the two `wheel' pyridine rings are tilted by 70.33 (3)° with respect to one another. It is the only known 1-1-4 structure, i.e. having 1, 1 and 4 spacer atoms between the rings. See Poole, Fronczek, Newkome & Watkins [Acta Cryst. (2006), E62, o4952-o4954].